Systems and methods for controlling operation of a valve

Abstract

A solenoid valve includes a solenoid coil, a poppet, and a drive circuit. A first semiconductor device of the drive circuit is controlled by a gate signal to control a coil current. A flyback circuit of the drive circuit includes a second semiconductor device in series with a diode. The second semiconductor device is controlled by a flyback control signal to: (i) enable the flyback circuit to maintain the coil current through the solenoid coil when the poppet transitions to a second position, and (ii) disable recirculation of the coil current through the solenoid coil when the poppet transitions to a first position. A controller is configured to transition the poppet to the second position using the gate signal, enable the flyback circuit using the flyback control signal, and reduce at least one of a duty cycle and a frequency of the gate signal when the flyback circuit is enabled.

What is claimed: 
     
       1. A solenoid valve comprising:
 a solenoid coil; 
 a poppet configured to transition within the solenoid valve between a first position and a second position based on a coil current flowing through the solenoid coil; and 
 a drive circuit comprising:
 a first semiconductor device controlled by a gate signal to control the coil current; and 
 a flyback circuit coupled with the solenoid coil, the flyback circuit comprising a second semiconductor device in series with a diode, wherein the second semiconductor device is controlled by a flyback control signal to: (i) enable the flyback circuit to maintain the coil current through the solenoid coil above a threshold value by recirculating the coil current through the solenoid coil, the second semiconductor device, and the diode when the first semiconductor device is controlled by the gate signal to transition the poppet to the second position, and (ii) disable recirculation of the coil current through the solenoid coil when the first semiconductor device is controlled by the gate signal to transition the poppet to the first position; and 
 
 a controller configured to transition the poppet from the first position to the second position using the gate signal, to enable the flyback circuit using the flyback control signal, and to reduce at least one of a duty cycle of the gate signal and a frequency of the gate signal when the flyback circuit is enabled. 
 
     
     
       2. The solenoid valve of  claim 1 , wherein the controller is further configured to transition the poppet from the second position to the first position using the gate signal, and to disable the flyback circuit using the flyback control signal. 
     
     
       3. The solenoid valve of  claim 2 , wherein the controller is further configured to generate the gate signal having a zero percent duty cycle to transition the poppet from the second position to the first position. 
     
     
       4. The solenoid valve of  claim 1 , wherein the flyback circuit is coupled in parallel with the solenoid coil to form a closed-loop circuit that excludes the first semiconductor device. 
     
     
       5. The solenoid valve of  claim 1 , wherein the controller is further configured to generate the gate signal with an initial duty cycle of 100 percent to transition the poppet from the first position to the second position. 
     
     
       6. The solenoid valve of  claim 1 , wherein:
 the gate signal comprises a pulse-width modulated (PWM) gate signal, and 
 the controller is further configured to reduce the duty cycle of the PWM gate signal to 25 percent or less when the flyback circuit is enabled. 
 
     
     
       7. The solenoid valve of  claim 1 , wherein:
 the first position corresponds to a closed position of the solenoid valve, and 
 the second position corresponds to an open position of the solenoid valve. 
 
     
     
       8. A method for controlling a solenoid valve having a solenoid coil and a poppet configured to transition within the solenoid valve, the method comprising:
 transitioning the poppet from a first position to a second position using a gate signal applied to a first semiconductor device coupled with the solenoid coil, wherein the first semiconductor device is controlled by the gate signal to control a coil current flowing through the solenoid coil; 
 enabling a flyback circuit coupled with the solenoid coil, the flyback circuit including a second semiconductor device in series with a diode, wherein enabling the flyback circuit maintains the coil current through the solenoid coil above a threshold value by recirculating the coil current through the solenoid coil, the second semiconductor device, and the diode; and 
 reducing at least one of a duty cycle of the gate signal and a frequency of the gate signal when the flyback circuit is enabled. 
 
     
     
       9. The method of  claim 8 , further comprising:
 transitioning the poppet from the second position to the first position using the gate signal; and 
 disabling the flyback circuit to disable recirculation of the coil current through the solenoid coil. 
 
     
     
       10. The method of  claim 9 , wherein transitioning the poppet from the second position to the first position comprises generating a zero percent duty cycle gate signal. 
     
     
       11. The method of  claim 8 , wherein transitioning the poppet from the first position to the second position comprises generating a 100 percent duty cycle gate signal. 
     
     
       12. The method of  claim 8 , wherein:
 the gate signal comprises a pulse-width modulated (PWM) gate signal, and 
 reducing at least one of the duty cycle of the gate signal and the frequency of the gate signal when the flyback circuit is enabled comprises reducing the duty cycle of the PWM gate signal to 25 percent or less when the flyback circuit is enabled. 
 
     
     
       13. The method of  claim 8 , wherein transitioning the poppet from the first position to the second position comprises transitioning the solenoid valve from a closed position to an open position. 
     
     
       14. A drive circuit for controlling a solenoid valve having a solenoid coil, the drive circuit comprising:
 a first semiconductor device controlled by a pulse-width modulated (PWM) gate signal to energize the solenoid coil and transition the solenoid valve from a first position to a second position; 
 a flyback circuit coupled with the solenoid coil, the flyback circuit comprising:
 a second semiconductor device controlled by a flyback control signal to: (i) enable the flyback circuit when the first semiconductor device is controlled by the PWM gate signal to hold the solenoid valve in the second position, and (ii) disable the flyback circuit when the first semiconductor device is controlled by the PWM gate signal to transition the solenoid valve to the first position; and 
 a diode coupled in series with the second semiconductor device to slow a decay of a current conducted through the solenoid coil while the solenoid valve is in the second position; and 
 
 a controller configured to generate the PWM gate signal to transition the solenoid valve from the first position to the second position, to enable the flyback circuit using the flyback control signal, and to reduce a duty cycle of the PWM gate signal when the flyback circuit is enabled. 
 
     
     
       15. The drive circuit of  claim 14 , wherein the controller is further configured to generate the PWM gate signal to transition the solenoid valve from the second position to the first position, and to disable the flyback circuit using the flyback control signal. 
     
     
       16. The drive circuit of  claim 15 , wherein the controller is further configured to generate the PWM gate signal having a zero percent duty cycle to transition the solenoid valve from the second position to the first position. 
     
     
       17. The drive circuit of  claim 14 , wherein the flyback circuit is coupled in parallel with the solenoid coil to form a closed-loop circuit that excludes the first semiconductor device. 
     
     
       18. The drive circuit of  claim 14 , wherein the controller is further configured to generate the PWM gate signal with an initial duty cycle of 100 percent to transition the solenoid valve from the first position to the second position. 
     
     
       19. The drive circuit of  claim 14 , wherein:
 the first position of the solenoid valve corresponds to a closed position for the solenoid valve, and 
 the second position of the solenoid valve corresponds to an open position for the solenoid valve. 
 
     
     
       20. The drive circuit of  claim 14 , wherein the controller is further configured to control the duty cycle of the PWM gate signal to maintain the current through the solenoid coil above a threshold value corresponding with the solenoid valve being held in the second position.